Document EP 2,895,110 describes a treatment device comprising a first implant and a second implant.
Such a device is generally implanted in a blood circulation conduit to treat areas having defects or diseases, such as dissecting aneurysms, occlusive lesions or compressions.
Endoluminal techniques are currently preferred for implanting the device, when they are practicable. Indeed, these techniques are less invasive for the patient and reduce the mortality and morbidity rates, as well as hospital stay durations.
Endoluminal techniques yield excellent results to treat lesions of the descending thoracic aorta, which is linear. However, in the case of the aortic arch, the implantation of the device using the endoluminal route poses some number of difficulties.
First, the first implant must be flexible enough to be able to adapt to the twists of the arterial shaft and to curve so that it can be satisfactorily brought into the aortic arch, then deployed while conforming to the anatomy of this vessel.
Next, several secondary implants must be mounted transversely through apertures arranged in the first implant. These secondary implants serve to fix the first implant axially for avoiding the risk of migration, and to cover the supra-aortic arterial branches in order to provide for revascularization of these branches.
To deploy a treatment device as cited above in a blood circulation conduit having a branch, it is known to first release the first implant into the blood flow conduit. An aperture arranged in the first implant is positioned facing the origin of each branch in which a second implant must be implanted. Then, the second implant is inserted into the aperture of the first implant through the branch. There are two insertion directions of the second implant into the aperture of the first implant, during placement of the treatment device. The second implant is either positioned in the aperture of the first implant while coming from the aperture of the first implant, or positioned in the aperture of the first implant while going toward the aperture of the first implant.
The second implant is next deployed and is fixed on the first implant via a retaining member that is for example a flange radially deployable at one end of the second implant.
To ensure proper working of the device once it is implanted in the body, it is necessary to produce a nearly complete seal between the inner contour of the aperture arranged in the first implant and the outer contour of the second implant.
This seal must be maintained all throughout the presence of the prosthesis in the patient, in particular when movements of the first implant and/or secondary implants occur.
Document WO 2005/034810 describes a prosthesis comprising an aperture and a deformable ring of the aforementioned type, positioned around the aperture, to keep a secondary implant in position relative to a primary implant in a treatment device. The deformability of the ring around 4% limits the effect of the elastic return of the steel secondary implant after it has been implanted. Such a ring nevertheless has a very limited deformability. In particular, the annular helical spring providing the elasticity of the ring is kept very rigidly in a bent edge of the opening, which greatly limits the deformability. The seal of the device is therefore not always perfect, in particular if the secondary implant moves, and/or is not aligned correctly with an axis perpendicular to the opening.